A steady stream of revelations about erroneous financial records and questionable ethics dating back to July has put the spotlight once again on New York Rep. Charles B. Rangel, prompting observers to wonder aloud whether it's time for Rangel to step down from his committee chairmanship.

The Democratic chairman of the powerful House Ways and Means Committee has been at the center of a seemingly endless swirl of questions about his activities. He came under fire this week after The New York Times reported that Rangel worked to protect a tax shelter for Nabors Industries, an oil company whose chief executive was pledging $1 million to a school bearing the congressman's name.

The executive, Eugene M. Isenberg, also personally pledged $200,000 to the City College of New York, where the public policy school is named for Rangel. Last year, the company won congressional approval to preserve its tax shelter in the Caribbean, saving Nabors tens of millions of dollars annually and depriving the federal treasury of $1.1 billion in revenues over a decade, according to a Congressional analysis by the nonpartisan Joint Committee on Taxation.

The recent disclosures have hurt Rangel's standing in the House, political watchers say.

"Republicans have tried to tie Democrats to Rangel, and some Democrats have begun to say privately that Rangel should step down in order to allow them to press ahead, undistracted and untainted, with President-elect Barack Obama's plans for dealing with the economy," Politico reports.

Problems surfaced for Rangel in July when the 19-term congressman acknowledged that he hoped his personal requests contained in letters to foundations and corporations would bring in donations to the academic center.

In a letter to the House ethics committee, Rangel confirmed that he sent at least 150 letters on congressional stationery to philanthropic and business leaders as part of his efforts to support the new Charles B. Rangel Center for Public Service at the City College of New York.

The congressman separately asked the House Ethics panel to look into his rental of four New York apartments at below-market rates, The New York Times reports. City and state guidelines require such dwellings to be used as a primary residence. Rangel has said that he would give up one apartment that he uses as a campaign office.

The congressman earlier had said that his living arrangements were a "personal issue" that the ethics panel should not examine.

In September, Rangel hired a forensic accountant to evaluate his financial disclosure and other records. Several Democrats on the Ways and Means Committee backed the longtime lawmaker as pressure mounted from Republicans urging him to step down.

In that same month, the House ethics committee launched a formal investigation to determine whether Rangel had broken House rules with several reported lapses in his personal finances and fundraising.

Last month, Rangel's legal team began probing whether the lawmaker received a homestead exemption on a house he owned in Washington while living in his rent-stabilized apartments in New York City, The New York Times reported. The New York Post first reported the existence of the exemption.